Two hundred and thirty-eight patients with essential hypertension from 39 general practice centres were treated in 7 double-blind trial with either oxprenolol 160 mg in a slow-release (SR) formulation with cyclopenthiazide 0,25 mg and potassium chloride 600 mg given once daily, or methyldopa 250 mg 3 times daily.

Intractable congestive cardiac failure, unexplained arrhythmias, changes in the cardiac silhouette and murmurs which change with position are all features which should arouse suspicion of a cardiac tumour.